Here is an update of Piggiesmalls 100 octane run after the ECU reset. My personal opinion ....

[SLPR S4]

is that the car is running a little lean. Scroll down to the bottom part of the thread.

My car ran really well on an AFR of 12 richening to ~11.3 leaning to 11.7. His CF's were much lower and the timing curve was very similar. His car was very fast. He pulled a 3.46 (I pulled a 3.28) BUT his logs had higher IAT's and the humidity was much higher. I think his car will be faster than mine in equal weather conditions.

Race gas = burns cooler = burns slower IIRC so it's ok to run more lean than on pump, correct?

• http://dtwaudi.com/viewtopic.php?t=8752

[box_of_partS4]

or so I've read, I'm just a keyboard tuner.

And that forum is still a waste of time.

[SLPR S4]

people on AW and looking and custom tuning companies, the range is actually 11.0 - 11.7.

This is a very good range for medium weather from the testing I've had (60 - 75 degree). It will richen even more in the hot weather and lean out in the cold.

P.

[Flyboy]

to burn slower, in which case whoever made the race gas pulled one over on you because you want race gas to burn faster. From a combustion standpoint, an AF ratio of 12-13 will produce the most power. There may be engine particular reasons that you don't go there, higher EGT's than your system will tolerate for instance, but that's the range where the most power will be produced.

[SLPR S4]

[box_of_partS4]

11-11.5 would be just a little extra gas to be on the safe side.

I found a bunch of info on 12.5ish being best for power a while back...lemme see if I can track it down.

Here's one I found, but not the in-depth one I read...still looking.

Although I could see why on a forced-induction application you might want to have more gas, what with the high cylinder pressures and a higher likelihood of preignition...

• http://www.innovatemotorsports.com/r...lock-chevy.php

[SLPR S4]

to be 11 - 11.3 down low in the midrange and 11.5 - 11.8 up high.

One fuel setting will be effected by weather conditions so it's best to tune the car in average weather.

With this AFR, my CF's and knock voltages were the lowest, my timing was the strongest and the car was the fastest.

I'm uber anal about logging all of the exact weather data to compare apples to apples.

Now, it's not to say that different cars could have completely different ranges given different setups and different regions of the country (altitude, etc.).

)

[Flyboy]

for the application to your car, there might be reasons to go richer than that. An AF ratio in that range may end up too hot for the ECUs liking and ends up pulling timing or adding fuel. In an ideal situation that would be the AF ratio that you'd shoot for, in practice you might find that you can't get that lean.

[SLPR S4]